Hundreds of dead fish have been seen floating belly-up on one of Britain’s most picturesque rivers.
One resident described the sight as “apocalyptic”.
The fish have been seen on a scenic stretch of the Cam between Elizabeth Bridge and Ditton Meadows, Cambridge.
The Environment Agency and Anglian Water suggested the cause may be low levels of dissolved oxygen in the water.
They dismissed fears pollution might be to blame, even though the half-mile stretch of river is close to a sewage outfall.
Simone Chalkley, a resident of Cambridge for 31 years, saw “maybe 100” dead fish while walking along the bank with her partner.
She added: “We just kept seeing one dead fish after another. Every few steps, there was one belly-up.
“I put a call into EA who said it’s been happening all over the UK and in Europe as well.
“It was a bit of a sad sight, really – I’ve never seen anything quite like it.”
Fish die-offs such as this are more common in the summer, because warm water holds less oxygen than cold.
The EA said: “It is suspected that low levels of dissolved oxygen after heavy rainfall were the cause of the fish deaths, not pollution.”